One- and two-dimensional modeling of ventilated façades with integrated photovoltaics

Abstract

Ventilated façades with integrated photovoltaic panels can be used to generate electricity, thermal energy, and for daylighting. Developing working models to study their performance for this thesis is the start of a long-term research project at Concordia University that aims to develop a better understanding of these systems. The research involved developing both a one-dimensional finite-difference model and a two-dimensional control-volume model. An algorithm was developed that determines iteratively the most appropriate convective heat transfer coefficient relationship to use for surfaces inside the cavity, based on system characteristics and temperature distributions. In the case of the 1D model, average, as opposed to local, coefficients are calculated. The 2D model provides a more detailed representation of the radiation heat transfer between surfaces inside the cavity, and includes vertical heat conduction within the system components. The 1D model on the other hand is more robust and faster to use. Validation was carried out which compared results obtained from the models to results found in literature, and from experiments. In addition, an inter-model comparison was done between the 1D and 2D models. Results show that the models come within the 10 to 21 percent uncertainty levels predicted by other researchers. After validation, the models were used to optimise the system performance, which showed that combined thermal-electric efficiencies of over 70% could be attained.